1. Field of the Invention
The present invention generally relates to a flexible print cable and a connector for the same, and especially relates to a flexible print cable and a connector for the same that realize high-speed transfer in single mode.
2. Description of the Related Art
In recent years, processing speed of digital information in electronic devices has been accelerating. Thus, there are demands for accelerating the transmission of digital signals in the electronic devices at, for example, approximately 800 MHz. It should be noted that a flexible print cable is often used in an electronic device for electrically connecting one part to another part.
As for the signal transmission, two methods are provided, i.e., a single mode transmission method in which a signal line is used for a single signal and a balanced transmission method in which two signals are generated for a single signal and the two signals are transmitted by two signal lines. The balanced signal transmission method is less influenced by noise compared to the single mode transmission method. The balanced signal transmission method can transmit the signal normally at a high frequency to a large extent compared to the single mode transmission method. Thus, the balanced signal transmission method is being adopted in fields in which a signal is transmitted at high speed.
However, the balanced signal transmission method needs a special signal processing circuit for processing the two signals. Accordingly, in order to apply the balanced transmission method to electronic devices adopting the single mode transmission method, it is necessary to change the design to a large extent. Therefore, it is difficult to apply the balanced signal transmission method to these electronic devices.
There are demands for a technology realizing a high speed digital signal transmission using the single mode transmission method faster than the conventional technology, i.e., realizing a flexible print cable less influenced by noise using the single mode transmission method.
FIG. 1 is a view illustrating a conventional flexible print cable 10 for single mode. The cable 10 is configured to include a signal line pattern 12 of parallel signal lines (S) on the upper surface of a polyimide film 11. In the drawing, a protection film is not shown.
A connector to which an edge of the cable 10 is connected is configured to include only signal contacts forming a line.
The above described conventional flexible print cable for the single mode is disclosed in Japanese Laid-Open Utility Model Application No. 8-10932.
Accordingly, the cable 10 is configured to include the adjacent signal line patterns 12 merely separated spatially. Therefore, crosstalk, reflection and the like constrain the signal to be actually transmitted at, for example, 200 MHz or less.
Further, the connector to which the end of the cable 10 is connected is configured to include signal contacts merely separated spatially. Accordingly, crosstalk, reflection and the like are easily generated.